1. Field of the Invention
The present invention relates generally to scanning transmission-type electron microscopes, and in particular to an improved detector for such microscopes.
2. Description of the Prior Art
Scanning transmission-type electron microscopes which include at least one annular detector disposed concentrically with respect to the optical axis of the microscope behind the specimen along the microscope beam path and an amplifier for amplifying the output signals generated by the detector are generally known in the art and are utilized for dark field or phase contrast pictures. See Rose, "Phase Contrast In Scanning Transmission Electron Microscopy", 39 Optik 416-436 (1974).